Pressure-sensitive copying paper

ABSTRACT

WHEREIN R1 and R2 each represents a member selected from the group consisting of an alkyl group having from one to five carbon atoms and a benzyl group; X represents a member selected from the group consisting of an alkyl group having from one to five carbon atoms and an aryl group, and Y represents a member selected from the group consisting of an alkyl group having from one to 17 carbon atoms, an aryl group, an amino group, an acylamino group and an alkoxy group having from one to five carbon atoms.   A pressure-sensitive copying paper comprising a support having coated thereon microcapsules containing an organic solvent solution of a compound which, when in contact with an electron acceptable solid acid, forms a color dye and is represented by the following formula:

United States Patent [72] Inventors Shlro Kimura;

Teruo Kobayashi; Sadao lshige, all of Kanagawa, Japan [21] Appl. No. 842,008 [22] Filed July 15,1969 [45] Patented Nov. 2, 1971 [73] Assignee Fuji Photo Film Co., Ltd.

Kanagawa, Japan [32] Priority July 15, 1968 [33] Japan [31] 43/49817 [54] PRESSURE-SENSITIVE COPYING PAPER 5 Claims, No Drawings [52] US. Cl 117/362, 1 17/369, 260/310 [51] Int. Cl B41m 5/22 [50] Field of Search 117/362, 36.8, 36.9; 260/310 R [56] References Cited UNITED STATES PATENTS 3,491,116 1/1970 Lin 260/326.14 3,499,902 3/1970 Coles et al 260/287 3,509,174 4/1970 Lin 260/326.14

Primary Examiner-Murray Katz Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT: A pressure-sensitive copying paper comprising a support having coated thereon microcapsules containing an organic solvent solution of a compound which, when in contact with an electron acceptable solid acid, forms a color dye and is represented by the following formula:

- alkyl group having from one to 17 carbon atoms, an aryl group, an amino group, an acylamino group and an alkoxy group having from one to five carbon atoms.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a pressure-sensitive copying paper and in particular, it is concerned with a pressure-sensitive copying paper using as a color former a compound represented by the following general formula:

n l l i in which R and R are alkyl groups of one to five carbon atoms or benzyl groups, X is an alkyl group of one to five carbon atoms or an aryl group, and Y is an alkyl group of one to 17 carbon atoms, an aryl group, an amino group, an acylamino group or an alkoxy group.

2. Description of the Prior Art Ordinary pressure-sensitive copying paper consists of an upper paper onto which is coated a substantially colorless organic compound having an electron-donating property and a color forming reactivity (hereinafter referred to as a color former") dissolved in an organic solvent and incorporated in microcapsules and a lower paper, onto which is coated electron-acceptable solid acid. If necessary, an intermediate paper layer is provided onto one side thereof is coated the colorformer-containing microcapsules and on the other side thereof is coated a solid acid, and a support on one side of which the microcapsules and solid acid are coated.

In the case of using the upper and lower paper in combination with the optional intermediate paper, the papers are pressed locally in such a manner that the microcapsules-containing layer and the solid acid-containing layer are contacted, whereby the microcapsules in this pressurized area are broken and the color former is reacted with the solid acid, thus color forming.

In the case of using a pressure-sensitive copying paper having the microcapsules and solid acid on the same side, the paper may be pressed for color forming by means of a typewriter, for example.

Examples of color formers coloring in red and blue are the following: leuco triphenylmethane derivatives, leuco methylene blue acyl derivatives, and triphenylmethane and xanthene phthalide derivatives having lactone rings. However, there are not many color formers coloring in yellow orange to orange red. These color formers have the following disadvantages. That is to say, o-hydroxybenzalacetophenone has a low color forming density. 2-(4-hydroxystyryl)-3,3-dimethyl- 3I-l-indole or 2-(4-acetamidestry1)-3,3-dimethyl-3H-indole (cf. Japan Pat. publication No. 21033/1966) has a high color forming density and relatively strong light resistance after color forming, but the light resistance before color forming and water resistance after color forming are weak. If a color former coloring in yellow-orange to orange-red is obtained which has a higher color density, higher color forming speed and stronger light resistance and water resistance before and after color forming than those known in the art, a pressuresensitive copying paper coloring in yellow-orange to orangered as well as a pressure-sensitive copying paper coloring in an optional color such as black or blue-black used together with a known color former coloring in red or blue will be given. This advantage enlarges the application of pressure-sensitive copying papers.

SUMMARY OF THE INVENTION It is the principal object of the present invention to obtain a pressure-sensitive copying paper coloring in yellow-orange to orange-red as well as to provide a pressure-sensitive copying paper coloring in an optional color such as black or blue-black together with a known red or blue color former by the use of a compound represented by the foregoing general formula.

We have discovered as a result of many studies on a color former coloringin yellow-orange to orange-red that the use of avcompound represented by the foregoing general formula as a color former leads to obtaining a pressure-sensitive copying paper coloring in yellow-orange to orange-red as well as a pressure-sensitive copying paper coloring in an optional color such as black or blue-black when used together with a known color former coloring in red or blue.

DETAILED DESCRIPTION OF THE INVENTION A pressure-sensitive copying paper according to the present invention using the compound of the foregoing general formula has an excellent stability in air before color forming, is free from coloring and lowering of the color forming ability, colored in yelloworange to orange-red immediately when contacted with an electron-accepting solid, acid, thus resulting in a high color density and is strongly resistant to light and water after color forming, When used together with a known color former coloring in red or blue, it colors in various colors such as black and blue-black without being desensitized.

Typical examples of the compound coloring in yelloworange to orange-red, represented by the foregoing general formula, are as follows;

Identification of the thus obtained compound with the molecular structure of the general formula is carried out by IR absorption spectrum and elementary analysis. The characteristic absorption of carbonyl in the lactone ring of these compounds appears near 1,755 cm.and neither the characteristic absorption of other carbonyl groups, except in the foregoing color former (9) having a carbonyl of amide, nor the characteristic absorption of a hydroxyl group was found. The result of the elementary analysis corresponds to the theoretical value as shown in the following synthesisexamples.

' SYNTHESIS EXAMPLE 1 Preparation of the color former general formula wherein 14.3 g. of 2-(4'-dimethylamino-2-hydroxybenzoyl) benzoic acid (1/20 mol) and 8.7 g. of 3-methy1-1- phenylpyrazolone (1/20 mol) were dissolved in 72 g. of concentrated sulfuric acid (94-96 percent) at below 45 C., reacted at 90i2 C. for 3 hours, and cooled to room temperature. The reaction solution was then poured into 800 g. of ice water, followed by filtering. The precipitate was extracted with 600 ml. of chloroform while being neutralized with an aqueous solution of caustic soda. The chloroform solution was washed with water several times and concentrated under reduced pressure to obtain 14.6 g. ofa colorless crystal melting at 296-298 C.

Analysis of the crystal:

Found (percent by weight): C, 73.41; H, 4.93; N, 9.80.

Calculated for C H N C, 73.74; H, 5.00; N, 9.92.

(1) represented by the SYNTHESIS EXAMPLE 2 Preparation of the color former general formula wherein SYNTHESIS EXAMPLE 3 Preparation of the color former (3 represented by the general formula wherein (2) represented by the General Formula H S O 4 H dehydrating reaction 18.8 g. (l/20 mol) of 2-(4-benzylehtylamino-2-hydroxybenzoyl) benzoic acid and 8.7 g. (1/20 mol) of 3-methyl-lphenylpyrazolone were reacted and processed in a similar manner as in Synthesis Example 1 to thus obtain 21.4 g. ofa colorless'crystal melting at l98-202 C.

Analysis of the crystal:

Found (percent by weight): C, 77.21; H, 5.1

N, 8.64. Calculated for C H N O C, 76.93; H, 5.04; N,

SYNTHESIS EXAMPLE 4 Preparation of the color former general formula wherein 15.7 g. (l/20 mol) of 2-(4-diethylamino-2-hydroxybenzoyl) benzoic acid and 9.4 g. (l/20 mol) of 3-rnethyl-l- (p-tolyl) -(p-tolyl) pyrazolone were reacted and processed in a similar manner as in Synthesis Example 1 to thus obtain 21.0 g. ofa colorless crystal melting at 186187 C.

Analysis of the crystal Found (percent by weight): C, 74.68;H, 5.78; N, 9.10.

Calculated for C H N O 74.82; H, 5.85; N, 9.03.

(4) represented by the SYNTHESIS EXAMPLE 5 Preparation of the color former general formula wherein (5) represented by the Analysis of the crystal:

Found (percent by weight): C, 60.70; H, 4.06; N, 7.68; CI,

Calculated for C ,,H C1 N O C, 60.61; H, 4.00; N, 7.57;

SYNTHESIS EXAMPLE 6 Preparation of the color former (6) represented by the general formula wherein 15.7 g. (l/20 mol) of 2-(4-diethylamino-2'-hydroxybenzoyl) benzoic acid and 15.4 g. (l/20 mol) of 3-ethoxy-l 2, 46-trichlorophenyl) pyrazolone were dissolved in 72 g. of concentrated sulfuric acid (94-96 percent) at below 40 C,

SYNTHESIS EXAMPLE 7 Preparation of the color former (7) represented by the general formula wherein 15.7 g. (l/20 mol) of 2-(4'-diethylamino-(2'-hydroxr ybenzoyl) benzoic acid and l 1.8 g. (l/20 mol) of 1,3-diphenyl-pyrazolone were reacted and processed in a similar manner as in Synthesis Example 1 to thus obtain 20.8 g. of a colorless crystal melting at 205 C.

Analysis ofthe crystal:

Found (percent by weight): C, 77.14; H, 5.26; N, 8.27.

Calculated for C H N O C, 77.17; H, 5.30; N, 8.18

SYNTHESIS EXAMPLE 8 Preparation of the color former (8 represented by the general formula wherein SYNTHESIS EXAMPLE 9 Preparation of the color former (9) represented by the general formula wherein 15.7 g. (l/20 mol) of 2-(4-diethylamino-2'-hydroxybenzoyl) benzoic acid and 15.6 g. (l/20 mol) of 3-(pchlorobenzoyl) amino-l-phenylpyrazolone were dissolved in 72 g. of concentrated sulfuric acid at below 40 C., reacted at 50 C. for 18 hours, neutralized with an aqueous solution of sodium carbonate at below 5 C. extracted with chloroform and the concentrated under reduced pressure to thus obtain 23.6 g. of a colorless crystal melting at 246-226 C.

Analysis of the crystal:

Found (percent by weight): C, 68.88 H, 4.49; N, 9.63: CI,

Calculated for C H,,CiN,O,, C, 69.09; H, 4.60; N, 9.48,

CI, 6.00. Y Calculated for C H CIMO C, 69.09; H, 4.60; N, 9.48,

SYNTHESIS EXAMPLE Preparation of the color former (l0) represented by the general formula wherein R,=R,='Et, and X ==Y =Me.

15.7 g. (l/ mol) of 2-(4'-diethylamino-2'-hydroxybenzoyl) benzoic acid and 5.6 g. l/20 mol) of 1,3-dimethylpyrazolone were reacted and processed in a similar manner as in Synthesis Example 9 followed by crystallizing from a mixed solvent of benzene-ether to thus obtain 15.3 g. of a colorless crystal melting at l77-178 C.

Analysis of the crystal:

Found (percent by weight): C, 70.81; H, 6.01; N, 10.77.

Calculated for c n n o C, 70.92, H, 5.95; N, 10.79.

SYNTHESIS EXAMPLE 1 1 Preparation of the color former (ll) represented by the general formula wherein and (331 8 2518 (0111M)- 15.7 g. (l/20 mol) of 2-(4'-diethylamino-2-hydroxybenzoyl) benzoic acid and 38.4 g. (l/20 mol) of 3-heptadecyl-l(p-phenoxyphenyl)pyrazolone were reacted and processed in a similar manner as in Synthesis Example 9 to ob tain a colorless syrupy material. The spectra of this material exhibited an absorption band at A max =505.485 millimicrons in 95 percent acetic acid solution.

Analysis of product:

Found (percent by weight): C, 78.06; H, 7.89; N. 5.41.

Calculated for C ,,H ,N O,, C, 78.24; H, 7.95; N, 5.48.

For the production of the pressure-sensitive copying paper of the present invention using the compound represented by the general formula, a method of making microcapsules by utilizing the complexed coacervation is employed, for example, which is disclosed in US. Pat. Nos. 2,548,366, 2,800,457 and 2,800,458 as being well-known to those skilled in the art. The instant invention is characterized by the use of the compound represented by the foregoing general formula as a color former. The characteristics of the pressure-sensitive copying paper are independent from the production method thereof. The amount of the color former used is generally 0.5-5 percent by weight based on the organic solvent.

The following examples are given in order to further illustrate the pressure-sensitive copying paper of the present invention using the typical color formers represented by the general formula, the examples being nonlimiting in nature.

EXAMPLE 1 Three grams of each of the color formers (I)-(Il) was The color former was dissolved in g. of trichlorodiphenyl. To the resulting solution were added 20 g. of gum arabic and g. of water at 50 C. to given an emulsion, further, 20 g. of acid-treated gelatin and 160 g. of water and then acetic acid were added, while stirring to adjust the pH to 5. Then, 500 g. of water was added thereto to advance the coacervation to form a thickened liquid film of gelatin-gum arabic around the oil drop of trichlorodiphenyl dissolving the color former. After adjusting the pH to 4.4, 3.8 g. ofa 37 percent aqueous solution of formalin was added thereto to harden the liquid film, and then an aqueous caustic soda solution was added to adjust the pH to 9 while being cooled to 10 C. and the resulting mixture was allowed to stand for 5-6 hours to complete the coacervation. The thus capsulized liquid was coated onto a sheet of paper by roll coating or by air knife coating and then dried. When the coated paper (upper paper) was brought into close contact with another sheet of paper (lower paper) coated with an electron-accepting solid acid such as acid clay. active clay, attapulgite, zeolite or bentonite and pressed by means of a pencil or typewriter, there instantaneously occurred a thick color formation on the pressed area of the lower sheet of paper. The color varied with the variety of the color formers although it was independent of the variety of the above-mentioned clays. A yellow-orange color was noted in the color formers (l), (2), (4,), (5), (6) and (10) orange in (3). (7). and (11); and orange-red in (8) and (9). These color formed dyes were scarcely faded even though exposed to direct sunlight for a long time or wetted with water. Moreover, a similar color from one to five carbon atoms and an aryl group, and Y formation was given thereto even when using a lower sheet of represents a member selected from the group consisting of an paper coated with an organic solid acid such as succinic acid, alkyl group having from one to 17 carbon atoms, an aryl gallic acid, p-toluenesulfonic acid, pentachlorophenol or group, an amino group, an acylamino group and an alkoxy phenol resin. No lowering of the color forming ability in the 5 group having from one to five carbon atoms. color former coated paper (upper paper) was found even 2- The pressure-sensitive copying paper as in claim 1 though heated at 100 C, fo 20 hours or exposed to h wherein said organic solvent is a member selected from the light for a long time. group consisting of chlorinated diphenyl, chlorobenzene and ethyleneglycol.

EXAMPLE 2 l 3. The pressure-sensitive copying paper as claimed in claim The procedure of example 1 was repeated, except that 1.51 l saldh electromacgpiable i a memtier g. of the color former (2) was used with the known color for- Se ecte mm t B group conslstmg 0 an acid c an acme mers, i.e., 0.3 g. of Benzoyl Leuco Methylene blue, 0.5 g. of i g l Succlmc acid tanmc l hite Green Lactone 0 7 of Cr stal Violet Lactone lc an Pema? Drop Ma ac 8- y t 5 4. A pressure-sensitive copying paper comprising a support 8 'P "Y auramme and 8- of Rhodamme B having coated thereon an electron-acceptable solid acid and Anilinolactam. When the thus-coated paper (upper paper) microcapsules containing an organic solvent solution of a was brought close Contact 11th a P p (lower P p compound which is in contact with said electron-acceptable coated with an electron-accepting solid acid, and then solid acid to from a color dye and is represented by the follow pressed, there rapidly occurred a color formation of black on i f l the lower sheet of paper.

EXAMPLE 3 R The procedure of example 1 was repeated, except that 0.3 N- f g. of the color former (4) and 0.7 g. of the color forrner (8) were used with 0.5 g. of Benzoyl Leuco Methylene Blue, 2.0 g.

of Crystal Violet Lactone and 0.8 g. of N-phenyl-leuco aul ramine. When the thus-obtained pressure-sensitive copying =0 paper was pressed by writing, there rapidly occurred a color I formation of blue-black.

EXAMPLE4 wherein R and R each represents a member selected from The procedure of example 1 was repeated, except that 1.8 the group consisting of an alkyl group having from one to five g. ofthe color former (7) was used with 1.2 g. ofRhodamineB 35 Carbon atoms and a benzyl g oup. X represents a b r Anilinolactam. The thus-obtained pressure-sensitive copying Selected from the group conslsnng of an alkyl g p havlng paper was colored in bright red. When using Rhodamine B from one to five carbon atoms and an y g p. and Y Anilinolactam alone, the color was bluish red that felt too represents a member Selected from the group consisting of dark to be d practically alkyl group having from one to 17 carbon atoms, an aryl group, an amino group, an acylamino group and an alkoxy EXAMPLE 5 group having from one to five carbon atoms.

5. A pressure-sensitive copying paper comprising and under paper having coated thereon an electron-acceptable solid acid and an upper paper having coated thereon microcapsules containing an organic solvent solution of a compound which is in contact with said electron-acceptable solid acid to form a color dye and is represented by the following formula:

The procedure of example 1 was repeated, except that the capsule was applied to a lower sheet of paper coated with a clay in place of using two sheets of paper. Pressing of the superposedly coated paper gave the same color formation as in example 1.

What is claimed is:

l. A pressure-sensitive copying paper comprising a support X having coated thereon microcapsules containing an organic i;\ solvent solution of a compound which, when in contact with N N an electron acceptable solid acid, forms a color dye and is i represented by the following formula: C Y

f 5 (':=o l l R, Y

J wherein R and R each represents a member selected from I the group consisting of an alkyl group having from one to five carbon atoms and a benzyl group, X represents a member selected from the group consisting of an alkyl group having from one to five carbon atoms and an aryl group, and Y wherein R and R each represents a member selected from represents a member selected from the group consisting of an the group consisting of an alkyl group having from one to five alkyl group having from one to 17 carbon atoms, an aryl carbon atoms and a benzyl group; X represents a member group, an amino group, an acylamino group and an alkoxy selected from the group consisting of an alkyl group having group having from one to five carbon atoms.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,6l7,335 Dated November 2, 1971 lnventofls) Shiro Kimura et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 34, after "coated" insert an line 36, after "provided" insert and Column 5, line 38, "and Y Me" should read and Y Me. line 60, "and Y Me" should read and Y Me. Column 7, line 2, "thus to" should read to thus Column 8, line 30, after "coacervation" insert technique line 31, "which is" should read that same line 31, "patent" should read Patent Column 9, line 44, "i" should read in Column 10, lines 44 and 45, "which is in contact" should read which, when contacted line 45, "acid to form" should read acid, forms Signed and sealed this 13th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents DRM USCOMM-DC scan-Pe a U75. GOVERNMENT PIINT NG OFFICE i 0-366-33 

2. The pressure-sensitive copying paper as in claim 1 wherein said organic solvent is a member selected from the grOup consisting of chlorinated diphenyl, chlorobenzene and ethyleneglycol.
 3. The pressure-sensitive copying paper as claimed in claim 1 wherein said electron-acceptable soil acid is a member selected from the group consisting of an acid clay, an active clay, attapulgite, zeolite, bentonite, succinic acid, tannic acid, gallic acid and pentachlorophenol.
 4. A pressure-sensitive copying paper comprising a support having coated thereon an electron-acceptable solid acid and microcapsules containing an organic solvent solution of a compound which is in contact with said electron-acceptable solid acid to from a color dye and is represented by the following formula:
 5. A pressure-sensitive copying paper comprising and under paper having coated thereon an electron-acceptable solid acid and an upper paper having coated thereon microcapsules containing an organic solvent solution of a compound which is in contact with said electron-acceptable solid acid to form a color dye and is represented by the following formula: 